1. Field of the Invention
The present invention relates to a lens barrel that is provided on an image pickup apparatus (optical apparatus) such as a camera, and the image pickup apparatus that is provided with the lens barrel.
2. Description of the Related Art
Conventionally, a film camera using a silver salt film, and a digital camera capable of shooting using an image pickup element have been known and have been widely used. Recently, for improvement of portability or like purposes, the internal mechanism of a camera has been technically developed so as to reduce the size thereof or increase the change ratio of the focal length (zoom ratio) thereof, and as a result, various techniques have been proposed.
In general, cameras include a zoom camera in which the focal length of a photographic lens is changeable, and a single focus camera in which the focal length is fixed. In theses cameras, there is generally provided a lens barrel which is capable of protruding and retracting the photographic lens, so as to enable size reduction during non-shooting time (when the power of the camera is off) or change in the focal length during shooting time (when the power of the camera is on).
Recently, to realize handy portability of cameras, there has been proposed various mechanisms focusing on the reduction of the size of a camera. To reduce the size of a camera, not only size reduction of a battery, a liquid crystal display device or the like provided in the camera, but also size reduction of a lens barrel is an important factor.
The size reduction of the lens barrel includes two kinds, such as reduction of the size in a direction of the optical axis, which is necessary for reducing the thickness of the camera, and reduction of the size in a radial direction, which is necessary for reducing the vertical and horizontal sizes of the camera. While such a size reduction is in progress, there has recently been dramatically increasing the number of cameras equipped with the anti-shake function, and accordingly, there have been proposed technical contrivances to make the anti-shake function compatible with a driving mechanism for opening and closing barriers conventionally provided in the lens barrel.
For example, Japanese Patent Laid-Open Publication No. 2001-215562 discloses a technique in which the opening and closing of the barriers is performed by providing a rotation interlocking section interlocked with the barriers, in a movable cam ring disposed at a location radially outward of a lens holding frame equipped with the shutter and a anti-shake mechanism (FIG. 12 attached hereto). In FIG. 12, a reference numeral 180 indicates a barrier drive ring, and a reference numeral 90 indicates a second cam ring.
Further, Japanese Patent Laid-Open Publication No. 2004-69991 discloses a technique in which the opening and closing of the barriers is usually performed by providing a rotation interlocking cam interlocked with the barriers, in rectilinear motion barrel disposed at a location radially outward of a lens holding frame equipped with the shutter and the anti-shake mechanism (see FIG. 13 attached hereto). In FIG. 13, a reference numeral 147 indicates a lens barrel component, a reference numeral 181 a driving member, and reference numerals 185 to 188 barrier members.
Further, as a technique for opening and closing the barriers, there has conventionally been proposed a mechanism in which the rotation interlocking section for opening and closing the barriers is protruded from a holding member of an image pickup element toward an object side, and the barriers are brought into contact with the rotation interlocking section, whereby the barriers are driven.
However, in the techniques disclosed in Japanese Patent Laid-Open Publication No. 2001-215562 and No. 2004-69991, it is required to interlock the rotation at a location radially outward of the lens frame equipped with the shutter and anti-shake mechanism, and hence it is necessary to increase the diameter of the barrier drive ring to the outer diameter of the lens frame, which is one factor causing an increase in the radial size of the lens barrel.
Further, in the mechanism in which the rotation interlocking section for opening and closing the barriers is protruded from the holding member of the image pickup element, it is possible to cause the rotation interlocking section to extend through the lens holding frame equipped with the shutter and anti-shake mechanism, in order to reduce the radial size of the lens barrel. However, it is difficult to arrange an extending-through portion of the rotation interlocking section in a construction including the shutter and the anti-shake mechanism.